1. Field of the Invention
The present invention relates to an information detector adapted for a camera using a film cartridge provided with a code pattern indicative of information about the film contained in the cartridge.
2. Description of the Prior Art
In the art of photography it is known to provide a film-magazine, -cassette or -cartridge with a coding or codings indicative of information proper to the film contained therein such as film sensitivity or film speed and to read the coding by means of a detector mounted in the camera. The film information introduced into the camera through the detector is automatically stored within the camera to use it later for exposure display, exposure control or other purposes at the time of picture-taking.
As an example, U.S. Pat. No. 4,173,401 has disclosed a combination of a film cartridge having a series of laterally spaced electrically conductive contacts and a camera provided with a detector having a series of laterally spaced electrical contact pins cooperating with the contacts. In this prior art film-information detecting means, the contacts arranged on the cartridge are partly covered with a coating of electrically insulating material to render the contacts partly electrically non-conductive to the contact pins. Thus, there is formed a pattern of conductive and non-conductive portions which constitutes a digital code indicative of the above-mentioned film information.
The information picked up by the contact pins is introduced into an electric circuit within the camera. In the circuit, the information is decoded and then stored in the camera. The film information stored within the camera in this manner is to be used to determine the exposure value when a picture is taken using the film. Since the stored information is a determinative factor to optimum exposure, it is absolutely necessary for such film information to be correctly transmitted to the electric circuit from the pins without fail. Otherwise the picture-taking will result in failure from the first frame to the last of the film. Main factors disturbing the correct transmission of the film information are bad contacts between electrical parts and the effects of electrical noise as generated by other electrical apparatus and instruments mounted in the camera. The frequency of wrong transmission of film information caused by these factors increases with increasing of the number of electric parts and also with increasing of the length of electric wiring. Thereby the reliability of the camera is reduced greatly.